The most popular input device is the keyboard, keypad, or the like, which is employed on cell phone, PDAs, portable computers, and desktop computer, for example. The key button is stamped with alphabetic, numeric, and other nomenclature, as well as for function keys. However, the functions assigned to the function keys are typically dependent on the computing context and are oftentimes assigned different functions for different contexts.
The ability to provide more flexibility in manufacturing and among the many different users was addressed by putting small liquid crystal display (LCD) screens on the tops of the individual keys. However, this presents many new problems by providing each of the keys with the LCD screen, LCD driver, LCD controller, and electronics board to integrate these components. Moreover, electronics boards need to be placed at the top of each of the mechanically actuated keys and connected to a system data bus via a flexible cable to accommodate the electrical connection during key travel.
Additionally, each of the keys must be individually addressed by a master controller to provide the electrical signals for controlling the LCD images for each of the key tops where the image is formed. This additional complexity impedes the mass production capability and low cost desired in a highly competitive marketplace. The LCD screens are flat, thereby preventing the design of concave or otherwise shaped keypads to provide tactile feedback to the user.